Binding an element of an array of an ObservableObject : 'subscript(_:)' is deprecated - swift

Question

I'm using an ObservableObject 'DataStore', which contains an array ('exampleList') of objects ('exampleObject').
#Published exampleList = [exampleObject]()
I'm calling the DataStore via #EnvironmentObject ('dataStore').
#EnvironmentObject var dataStore = DataStore()
Then I iterate the list with
ForEach(0..<dataStore.exampleList.count) { index in ....
To bind element of item to a detail view, I'm doing like this:
DetailView(itemBinding: $dataStore.exampleList[index])
Until Xcode11 beta 4, it worked perfectly. Since XCode11 beta 5, it still works but Xcode gives me this alert:
'subscript(_:)' is deprecated: See Release Notes for a migration path
I tried with simpler stuff, with a simple #State var containing an array of strings, and it's the same issue: when calling an element of this array, and trying to use the value into a TextField:
TextField("test", text: $test[0])
I get the same alert.
I don't understand how to fix it. Does that mean that we no longer can bind values inside an array?
Then, how can we iterate an array and bind a specific item?
This is my first question on Stack Overflow, I apologize if my question is clumsy...
Thanks a lot for your answers, I'm using Stack Overflow for years, it's amazing, I always find existing and helpful answers, but it is the first time I can't find any, that's why I'm asking.

Answer 1

Xcode 11, beta 6 UPDATE:
Good news! Just as I suspected, in beta 6, the Binding conformance to MutableCollection has been been replaced with something else. Instead of conforming to MutableCollection, it now let your access the elements via #dynamicMemberLookup. The result is you now can keep doing $text[3] and no longer get a warning! It seems this question can be closed now.
Xcode 11, beta 5. Old answer:
I finally got some time to investigate this a little. As I mentioned in the comments, I think it would be wise to wait until the Collection conformance is completely removed (or replaced with something else). But just to satisfy our curiosity, I have created an extension on Binding, that I think does what the current Collection conformance does. The only difference is that, instead of accessing through a subscript, I implemented a function called element(_ idx: Int) to get a Binding<T> to the element.
If one day the conformance is completely removed, I may change the implementation, and conform to Collection myself. I cannot do it now, because it would conflict with the existent (and deprecated) implementation. For the time being, I think this demonstrate how to handle the warnings if you absolutely want to get rid of them.
Just to be clear. I am not using this code. As long as I can still access the elements through the subscript, I will still do it and ignore the warnings. This is just for academic purposes.
The extension is:
extension Binding where Value: MutableCollection, Value.Index == Int {
func element(_ idx: Int) -> Binding<Value.Element> {
return Binding<Value.Element>(
get: {
return self.wrappedValue[idx]
}, set: { (value: Value.Element) -> () in
self.wrappedValue[idx] = value
})
}
}
And it can be used like this:
struct MainView: View {
#Binding var text: [String]
var body: some View {
TextField("", text: $text.element(0))
TextField("", text: $text.element(1))
TextField("", text: $text.element(2))
}
}

Answer 2

I had to bind the array of an observable object recently, didn't get any warnings on stable XCode11. I did it like this
struct ScheduleTimer: Identifiable {
var id: Int
var name: String
var start: Date
var end: Date
var isActive: Bool
}
struct ScheduleView: View {
#ObservedObject var scheduleController = ScheduleController()
var body: some View {
NavigationView {
Form {
ForEach(scheduleController.timers) { timer in
ScheduleForm(scheduleController: self.scheduleController, timer: timer)
}
}
}
}
}
struct ScheduleForm: View {
#ObservedObject var scheduleController: ScheduleController
var timer: ScheduleTimer
var scheduleIndex: Int {
scheduleController.timers.firstIndex(where: { $0.id == timer.id })!
}
#State var start = Date()
var body: some View {
Section(header: Text(self.scheduleController.timers[scheduleIndex].name)){
DatePicker("From", selection: self.$scheduleController.timers[scheduleIndex].start, displayedComponents: .hourAndMinute)
DatePicker("To", selection: self.$scheduleController.timers[scheduleIndex].end, displayedComponents: .hourAndMinute)
Toggle(isOn: self.$scheduleController.timers[scheduleIndex].isActive) {
Text("")
}.toggleStyle(DefaultToggleStyle())
}
}
}
class ScheduleController: ObservableObject {
#Published var timers = [ScheduleTimer]()
...